Scientists believe genes may contain the secret of why some people live to be 100 or more.

People's lifestyles clearly play a part in determining whether or not they live to a ripe old age, but a Boston-based firm is to study 100-year-olds to try to identify the genes that enable people to resist the diseases of ageing which affect the rest of the population.

Researchers from the company Centagenetics are looking at hundreds of DNA samples. They hope that by identifying "longevity genes", drugs could be developed to counteract those diseases.

Although many people in western societies live to 70, only a small number live to become centenarians and remain healthy.

'Don't get married'

Thomas Perles, head of Centagenetics, said finding genes could provide "a great window into understanding the biochemical pathways that lead to disease", and therefore, maybe, help develop drugs that could interfere with those pathways and help people maintain their health for as long as possible.

"In our case, it's not the disease we're after; it is this incredible survival advantage of getting to old age in good health," Thomas Perles said.

Eddie Bernstein, 99, from Boston, is set to take part in the study. He is proud to say he still drives, cooks for himself and only uses glasses to read small print.

"I take care of myself," he said. "I go out two or three times a week to eat, I cook myself and the only trouble I have is the arthritis in my feet."

His father died at 101, so Eddie is determined to live to at least 102.
He puts his longevity down to chewing on cigars and spending time with his friends. And he advised staying single had helped him live a long life: "My secret is don't get married."